Liquid level indicator using lights

Abstract

An indicator assembly for indicating the level of liquid in a tank includes one or more columns of lights that are turned on or off as the level of liquid in the tank rises and falls. The lights may be turned on and off by the passage of a magnetic float that changes the state of magnetically actuatable switches, such as Hall effect transistors, that are associated in a one-to-one relationship with the lights. If two columns of lights are used, they may be of different colors.

1 . A method of indicating level of fluid in a tank using an indicator having a float that rises and falls with the level of fluid in said tank, comprising the steps of: 
 turning on a fluid-present light corresponding to a vertical position of said float; and    turning on a fluid-not-present light at all other positions.    
     
     
         2 . The method as set forth in  claim 1 , wherein said fluid-present lights are different in color than said fluid-not-present lights.  
     
     
         3 . The method as set forth in  claim 1 , wherein said float provides two opposing magnetic fields that move vertically as said float rises and falls.  
     
     
         4 . The method as set forth in  claim 3 , wherein said step of turning on the fluid-present light further comprises the step of: 
 actuating a magnetically actuatable switch with one of said magnetic fields of said float.    
     
     
         5 . The method as set forth in  claim 4 , wherein said magnetically actuatable switch is a latching Hall effect transistor.  
     
     
         6 . The method as set forth in  claim 4 , wherein said magnetically actuatable switch is selected from the group consisting of an A3187EUA-type, UGN3175XUA-type and UGN3177XUA-type Hall effect transistor.  
     
     
         7 . The method as set forth in  claim 4 , further comprising the steps of: 
 outputting a level-indication signal based on the actuating of said magnetically actuatable switch to a microprocessor; and    controlling said fluid-present light and said fluid-not-present light using a control signal from said microprocessor which is based on said level-indication signal.    
     
     
         8 . The method as set forth in  claim 3 , wherein said step of turning on the fluid-not-present light includes the step of: 
 driving a magnetically actuatable switch to a default state using a current spike.    
     
     
         9 . The method as set forth in  claim 8 , wherein said magnetically actuatable switch is a latching Hall effect transistor and wherein said default state is off.  
     
     
         10 . The method as set forth in  claim 1 , wherein said indicator is powered using a negative input voltage.  
     
     
         11 . The method as set forth in  claim 1  further comprising the step of: 
 providing said indicator with a negative DC voltage upon power up.    
     
     
         12 . The method as set forth in  claim 11 , wherein said providing step includes providing about −18 volts DC and about 0.35 amps to said indicator.  
     
     
         13 . The method as set forth in  claim 1 , further comprising the subsequent steps of: 
 turning off said fluid-not-present light located below the level of fluid in said tank; and    turning on said fluid-present light located below the level of fluid in said tank.    
     
     
         14 . The method as set forth in  claim 13 , wherein said step of turning off said fluid-not-present light located below the level of fluid in said tank and said step of turning on said fluid-present light located below the level of fluid in said tank include the steps of: 
 draining fluid from a gauge which houses said float such that said float moves past said fluid-not-present light located below the level of fluid in said tank and said fluid-present light located below the level of fluid in said tank; and    filling said gauge with said fluid from said tank.    
     
     
         15 . The method as set forth in  claim 14 , wherein said draining step is manually performed.  
     
     
         16 . The method as set forth in  claim 14 , wherein said draining step is automatically performed.  
     
     
         17 . The method as set forth in  claim 13 , wherein said steps of turning off said fluid-not-present light located below the level of fluid in said tank and turning on said fluid-present light located below the level of fluid in said tank are performed using signals from a microprocessor.  
     
     
         18 . The method as set forth in  claim 13 , wherein said steps of turning off said fluid-not-present light located below the level of fluid in said tank and turning on said fluid-present light located below the level of fluid in said tank include the step of: 
 moving a magnet past said fluid-not-present light located below the level of fluid in said tank and said fluid-present light located below the level of fluid in said tank.    
     
     
         19 . The method as set forth in  claim 18 , wherein said moving step is manually performed.  
     
     
         20 . The method as set forth in claims  18 , wherein said moving step is automatically performed.  
     
     
         21 . The method as set forth in  claim 13 , wherein said steps of turning off said fluid-not-present light located below the level of fluid in said tank and turning on said fluid-present light located below the level of fluid in said tank include the step of: 
 pulling said float downwardly past said fluid-not-present light located below the level of fluid in said tank and said fluid-present light located below the level of fluid in said tank.    
     
     
         22 . The method as set forth in claims  21 , wherein said pulling step is manually performed.  
     
     
         23 . The method as set forth in  claim 21 , wherein said pulling step is automatically performed.  
     
     
         24 . The method as set forth in  claim 13 , wherein said steps of turning off said fluid-not-present light located below the level of fluid in said tank and turning on said fluid-present light located below the level of fluid in said tank include the step of: 
 pushing said float downwardly past said fluid-not-present light located below the level of fluid in said tank and said fluid-present light located below the level of fluid in said tank.    
     
     
         25 . The method as set forth in claims  24 , wherein said pushing step is manually performed.  
     
     
         26 . The method as set forth in  claim 24 , wherein said pushing step is automatically performed.  
     
     
         27 . The method as set forth in  claim 1 , wherein said fluid-not-present light and said fluid-present light are arranged to form a circular shape.  
     
     
         28 . The method as set forth in  claim 1 , wherein said fluid-not-present lights and said fluid-present lights are arranged to form an arcuate shape.  
     
     
         29 . The method as set forth in  claim 1 , wherein said fluid-not-present lights and said fluid-present lights are arranged to form a linear shape.  
     
     
         30 . A liquid level indicator for indicating level of liquid in a tank, comprising: 
 a fluid-present light located at a discrete vertical position;    a fluid-not present light positioned and associated with said fluid-present light; and    a magnetically actuatable switch in electrical connection with said fluid-present light and said fluid-not-present light,    wherein said magnetically actuatable switch latchedly turns on said fluid present-light and turns off said fluid-not-present light as a magnetic device passes said magnetically actuatable switch in a first direction, and    wherein said magnetically actuatable switch latchedly turns off said fluid-present light and turns on said fluid-not-present light as said magnetic device passes said magnetically actuatable switch in a second direction.    
     
     
         31 . The liquid level indicator as set forth in  claim 30 , wherein said magnetically actuatable switch is a latching Hall effect transistor,  
     
     
         32 . The liquid level indicator as set forth in  claim 31 , wherein said magnetically actuatable switch is a three-pin Hall effect transistor.  
     
     
         33 . The liquid level indicator as set forth in  claim 32 , wherein a control transistor is disposed in series with said fluid-not-present light and wherein a gate of said control transistor is electrically tied to an output of said three-pin Hall effect transistor.  
     
     
         34 . The liquid level indicator as set forth in  claim 32 , wherein a ground pin of said three-pin Hall effect transistor is electrically tied to a VCC pin of a different serially-connected Hall effect transistor.  
     
     
         35 . The liquid level indicator as set forth in  claim 32 , wherein said fluid-present light is electrically connected between an output pin of said three-pin Hall effect transistor and a ground pin of a different serially-connected Hall effect transistor.  
     
     
         36 . The liquid level indicator of  claim 32 , wherein said fluid-present light and said fluid-not-present light are arranged as a pair at said discrete vertical position.  
     
     
         37 . The liquid level indicator of  claim 36 , wherein in each pair, one and only one of said lights is on.  
     
     
         38 . The liquid level indicator as set forth in  claim 31 , wherein said magnetically actuatable switch is a four-pin Hall effect transistor.  
     
     
         39 . The liquid level indicator as set forth in  claim 30 , wherein said liquid level indicator is operable to be powered by negative DC voltage.  
     
     
         40 . The liquid level indicator as set forth in  claim 30 , wherein a ground pin of said magnetically actuatable switch is electrically connected to a negative DC voltage.  
     
     
         41 . The liquid level indicator as set forth in  claim 30 , wherein a VCC pin of said magnetically actuatable switch is electrically connected to ground.  
     
     
         42 . The liquid level indicator of  claim 30 , wherein the liquid level indicator includes a plurality of fluid-present lights and corresponding fluid-not-present lights at different discrete vertical positions.  
     
     
         43 . The liquid level indicator of  claim 30 , wherein said fluid-present light and said fluid-not-present light are arranged as a pair at said discrete vertical position.  
     
     
         44 . The liquid level indicator of  claim 43 , wherein in each pair, one and only one of said lights is on.  
     
     
         45 . The liquid level indicator of  claim 30 , wherein said fluid-present light, said fluid-not-present light and said magnetically actuatable switch form a group, and wherein said liquid level indicator includes a plurality of groups.  
     
     
         46 . The liquid level indicator of  claim 45 , wherein said plurality of groups are electrically connected in series.  
     
     
         47 . The liquid level indicator of  claim 45 , wherein a predetermined number of groups are electrically connected in series to form a branch, and wherein said liquid level indicator includes a plurality of branches electrically connected in parallel.  
     
     
         48 . The liquid level indicator of  claim 47 , wherein each one of said branches is electrically connected between ground and a negative input voltage.  
     
     
         49 . The liquid level indicator of  claim 30 , further comprising: 
 a floating device containing said magnetic device, wherein said floating device is operable to float at a vertical level substantially equal to a vertical level of the liquid in said tank as said liquid level rises and falls.    
     
     
         50 . The liquid level indicator of  claim 30 , wherein said magnetic device provides: 
 a first magnetic field flowing in a first direction; and    a second magnetic field, below said first magnetic field and flowing in a second direction opposite to said first direction.    
     
     
         51 . The liquid level indicator of  claim 50 , wherein said first magnetic field is provided by a first magnet and said second magnetic field is provided by a second magnet.  
     
     
         52 . The liquid level indicator of  claim 50 , wherein said first magnetic field turns said magnetically actuatable switch off which turns off said fluid-present light and turns on said fluid-not-present light; and 
 wherein said second magnetic field turns said magnetically actuatable switch on which turns on said fluid-present light and turns off said fluid-not-present light.    
     
     
         53 . The liquid level indicator of  claim 30 , wherein said liquid level indicator is inherently safe.  
     
     
         54 . The liquid level indicator as set forth in  claim 30 , wherein said fluid-not-present light and said fluid-present light are remotely located from said magnetically actuatable switch.  
     
     
         55 . A power supply for a liquid level indicator, comprising: 
 a power input having an input voltage;    a voltage step-down circuit electrically connected to said power input for stepping down said input voltage to a stepped-down voltage;    an amplification circuit to adjust the stepped-down voltage to a predetermined voltage;    a voltage regulation circuit electrically connected to said amplification circuit for producing a regulated output voltage and output current; and    a voltage splitting circuit disposed electrically between said voltage step-down circuit and said amplification circuit,    wherein said voltage splitting circuit is operable to produce multiple outputs having substantially equal voltage,    wherein said amplification circuit produces multiple outputs having substantially equal voltage, and    wherein said voltage regulation circuit produces multiple outputs having substantially equal voltage and current.    
     
     
         56 . The power supply as set forth in  claim 55 , further comprising: 
 a voltage conversion circuit operable to convert an AC voltage to DC voltage, wherein said input voltage is an AC voltage.    
     
     
         57 . The power supply as set forth in  claim 56 , wherein said regulated output voltage is a negative DC voltage.  
     
     
         58 . The power supply as set forth in  claim 57 , wherein said regulated output voltage is about negative 18 volts DC and said regulated output current is about 0.35 amps.  
     
     
         59 . The power supply as set forth in  claim 56 , wherein said regulated output voltage is a positive DC voltage.  
     
     
         60 . The power supply as set forth in  claim 56 , wherein said voltage conversion circuit is a four diode rectifier.  
     
     
         61 . The power supply as set forth in  claim 55 , wherein said input voltage is a DC voltage and wherein said regulated output voltage is a negative DC voltage.  
     
     
         62 . The power supply as set forth in  claim 61 , wherein said regulated output voltage is about negative 18 volts DC and said regulated output current is about 0.35 amps.  
     
     
         63 . The power supply as set forth in  claim 61 , wherein said power supply is intrinsically safe.  
     
     
         64 . The power supply as set forth in  claim 55 , further comprising: 
 an electromechanical switch disposed electrically between said amplification circuit and said voltage regulation circuit operable to provide a current spike.    
     
     
         65 . A method of setting fluid-present lights and fluid-not-present lights located below the level of fluid in a tank after power up, comprising the steps of: 
 turning off each of said fluid-not-present lights, that is turned on as a result of power up; and    turning on each of said fluid-present lights, that is not turned on as a result of power up.    
     
     
         66 . The method as set forth in  claim 65 , wherein said steps of turning off each of said fluid-not-present lights and turning on each of said fluid-present lights include the step of: 
 draining fluid from a gauge which houses a float having a magnetic device such that said float moves past each of said fluid-not-present lights located below the level of fluid in said tank and said fluid-present lights located below the level of fluid in said tank.    
     
     
         67 . The method as set forth in  claim 65 , wherein said steps of turning off each of said fluid-not-present lights and turning on each of said fluid-present lights are performed using signals from a microprocessor.  
     
     
         68 . The method as set forth in  claim 65 , wherein said steps of turning off each of said fluid-not-present lights and turning on each of said fluid-present lights include the step of: 
 moving a magnetic device past each of said fluid-not-present lights located below the level of fluid in said tank and said fluid-present lights located below the level of fluid in said tank.    
     
     
         69 . The method as set forth in  claim 65 , wherein said steps of turning off each of said fluid-not-present lights and turning on each of said fluid-present lights include the step of: 
 pulling a float having a magnetic device downwardly past each of said fluid-not-present lights located below the level of fluid in said tank and said fluid-present lights located below the level of fluid in said tank.    
     
     
         70 . The method as set forth in  claim 65 , wherein said steps of turning off each of said fluid-not-present lights and turning on each of said fluid-present lights include the step of: 
 pushing a float having a magnetic device downwardly past each of said fluid-not-present lights located below the level of fluid in said tank and said fluid-present lights located below the level of fluid in said tank.